Rubber is one of the most useful materials today and has elastic characteristics. However, natural rubber produced from rubber trees has limited production, whereby synthetic rubber for replacing the same has been used in various fields. The synthetic rubber refers to a polymer material having the same or similar physical properties as natural rubber. The synthetic rubber includes butadiene rubber, styrene-butadiene rubber, acrylonitrile butadiene rubber or butyl rubber, and the like.
In producing the synthetic rubber, methods such as suspension polymerization, emulsion polymerization, bulk polymerization and solution polymerization are used. However, polymerization methods for producing the synthetic rubber have each the following problems.
For example, when it is produced by bulk polymerization, the viscosity of the reactant rises sharply to cause a mechanical load increase, as the reaction progresses and upon further polymerization, it is difficult to control the reaction temperature, so that there is a disadvantage that commercial mass production is difficult.
Furthermore, in the case of suspension polymerization, an initiator (catalyst) is dissolved in a monomer, the monomer is dispersed in water, and then a dispersant is incorporated to stabilize the formed suspension. In all the suspension polymerization methods, a surfactant, which disperses the monomer particles such that the polymer does not fuse and aggregate upon reaction, is used and various dispersants such as water insoluble fine inorganic materials and organic materials are used depending on the monomers to be polymerized, so that there is a disadvantage that purity of the final product is lowered.
Therefore, in order to mass-produce synthetic rubber, the solution polymerization method or the emulsion polymerization method using a continuous polymerization reactor is mainly used.
For recovery and reuse of unreacted monomers and solvents after the reaction, a method such as steam stripping and distillation is used. An explanation of steam stripping to recover solvents in this way is well described in Korean Laid-Open Patent Publication No. 2004-0042561. Generally, there are various methods for recovering the polymer produced after a synthetic rubber production reaction, but as a typical method, a stripping process, in which the polymer solution is introduced into a high-temperature water and the solvent is volatilized and removed together with water vapor using steam to recover the polymer, is used.